Excerpt from Screw Thread Cutting The lead of a screw thread is the distance the screw will move forward in a nut if turned around one full revolution. It is clear that for a single-threaded screw the pitch and the lead are equal, as the screw would then move forward the distance from one thread to the next if turned around once. In a double-threaded screw, however, the screw will move forward two threads, or twice the pitch, so that in a double-threaded screw the lead equals twice the pitch. In a triple threaded screw the lead equals three times the pitch, and so forth. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.